Natural, from hoof to food.Since 1993,Glerups have been made with nature's wonder fibre, 100% pure wool. Glerups select wool is gently washed in soft water, made into socks and felted with steam to the shape of your foot. Soft calfskin soles protect the wool for longer wear. Leather soles also take the "slip" out of the slippers and provide a step that's as whisper soft as it is cozy. Glerups can be washed by hand in cold or luke warm soapy water. Use regular powdered laundry detergent, or for more stubborn grease stains, use liquid dish detergent. Leave them in the water for 15 minutes, rub them clean, rinse out the soap and spin dry. Put your feet in the moist shoes and pad them into shape. Gentle warning: Please never use Hot water; the wool will shrink and lose its shape. Washing wool is at your own risk.